Ditto

Ditto is a very special Pokemon, maybe not SO much for battling, but it can be a nuisance. This Pokemon has the ability to transform into ANY other Pokemon during battle, copying all of the opponents moves and stats. What really makes this Pokemon special though, is that when in a daycare, it can breed with almost any other Pokemon. This does not include egg group X, which is all legendaries (Excluding Manaphy.) and genderless Pokemon.